Device for reburning exhaust gases



Jan. 5, 1932. c, HYATT 1,839,879

DEVICE FOR REBURNING EXHAUST GASES Filed May 6. 192'? 2 Sheets-Sheet 1 \jlk non 00 o 00 Q 000 \J A S; o o o \N z o o 0 INVENTOR LOUIS (I. HYATT ATTORNEY Jan. 5, 1932.

L. c HYATT 1,839,879

DEVICE FOR REBURNING EXHAUST GASES Filed May 6. 1927 2 Sheets-Sheet 2 INVENTOR LOUIS C. HYATT law ATTORNEY Patented .Ian. 5, 1932 PATENT. OFFICE LOUIS G. HYAT'I, OF ALBANY, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, T

CONSOLIDATED OAR-HEATING COMPANY, INC., OF ALBANY, NEW YORK, A CORPORA- men or NEW YORK nnvren FOR annuanme nxnaus'r GASES Application filed May 6, 1927. Serial No. 189,820.

In the accompanying drawings Figure 1 is a sectional view diagrammatically illustrating the invention. Figures 2 and 3 are similar views illustrating slight 5 modifications.

My invention relates to the art of burning exhaust gases, particularly those from an internal-combustion engine, either to provide heat or to purify the exhaust of its poisonous and obnoxious ingredients, or for both purposes. It involves novel apparatus and novel methods, and may also prove available for exhaust gases from other sources than an internal combustion engine.

It is now known that the exhaust gases from an internal-combustion engine contain a greater or less percentage ofunburned fuel which can be utilized for a second combustion. It has been proposed to ignite the exhaust after mixing air with it by an external agency, such as an electric spark, and to continue the combustion by means of the flame thus inaugurated. Thereby the combustion will continue even if the electric spark is cut off. In practice, however, much difliculty has been encountered in maintaining the said combustion due to several unique peculiarities of the said exhaust. One of such peculiarities is that the exhaust is not under a constant pressure but comes in puffs corresponding to the consecutive explosions in the engine cylinders. Moreover, the pressure when the engine is'working hard is much greater than when it is running light, while even under light loads its velocity is high. Another peculiarity is that the composition of the exhaust varies widely under the different operating conditions of the engine and it also difiers widely in the several different makes of engine. A serious result of this is that the combustion of the exhaust can not be maintained continuously but will go out at unexpected times and will not be resumed automatically even if an electric spark is' present. These two difficulties of variable pressure and variable composition I have successfully overcome by the means hereinafter described. 7

The ressurewariation 1 involves wide changes 1n the velocity of the exhaust stream the combustion going. In brief, the stream 'ones of large diameter have a greater surface,

and in the volume of gas to be treated. I

have discovered that the relation of stream velocity to the velocity of flame propagation is largely responsible for the inability to keep velocity may become so great that the flame propagation can not keep pace with it, the incoming flow of gas which has not yet been raised iii-temperature up to the kindling point becomes so great that the flame is extinguished. On the other hand, it is not feasible to limit the stream velocity by obstructing to any material extent the carrying capacity of thepipe or conduit through which it passes because the resulting back-pressure would impair the action of the engine. In exhaust burners of this type heretofore proposed the exhaust has been directed through a zig-zag route comprising a set of tube sections through which the exhaust stream passes seriatim', the resistance presented by the several sections being the added sum of the individual ones. Moreover, the said sections have been arranged concentrically and the outer (,5 while the friction of the gas-flow varies as the square of the surface area. Hence in such burners the retarding efiect becomes excessive as the volume and velocity rises. It has also been diflicult to maintain an adequate mixing space for the incoming gas and air streams under the violent fluctuations of stream velocity and the resulting dislocation of the flame. Referring to Fig. 1 of the drawings, I will first describe the construction by which I overcome the aforesaid pressure and velocity difliculties. In this figure, 1 represents the exhaust pipe. At its outer extremity this pipe is surrounded by a conical sleeve A, suitably mounted on the pipe but separated therefrom by an annular space. Outside of sleeve A. is a tube B closed around pipe 1 at'it" lefthand end and provided with slots 10 covered by a movable tubular damper 11. The air to be mingled with the exhaust enters through i said slots 10 by injector suction under the adjusting control of the damper. The tube B is continued to the right by conical tube sections C and'E with a cylindrical tube D inaway the hot and purified gas-stream. At

the entrance end of D is located a spark-plug 14, which is preferably kept in actionby any known means. For instance, it may be included in the common ground connection of the several spark-circuits of'the engine. It will be understood that the exhaust gas emerges from the tube 1 in a compact stream comparable to the water-stream from a firehose, having a fixed direction from which it is not readily diverted. This effect becomes more pronounced as the Velocity rises. Assuming that the gas becomes ignited at sparkplug 14, the starting point of the flame will tend to vibrate back and forth violently with the violent fluctuations in velocity of the gas stream. This is due to the effort of the flame to maintain itself the flame will move to the left as the stream velocity decreases and to the right as it increases until said velocity becomes so great that the flame can not follow owing to the limit in velocity of flame-propagation. In order to maintain an adequate mixing chamber 12 in tube A, I place at the right of said chamber a Davy-screen 13 that will stop the leftward play of the flame at that point. Within tubes D, E and F, I place what I term a stabilizer which consists of a tube G, shown as slightly tapered, formed of perforated metal, or at least of metal perforated at each end as shown. The perforations are preferably of increasing size from the central imperforated zone outward towards each end. Across the centre of tube G is a conical deflector H which is also formed of perforated metal. The diameter of tube G is such as to leave a free annular space around it inside of tube D. This space is gradually reduced to the end of tube E, but not closed.

The action of the apparatus thus. far de scribed is as follows :-At low exhaust-velocity the gas will still emerge from exhaust pipe 1 in the form of a compact jet, being, however, able to receive into it, in mixing chamber 12, the air sucked through the slots 10 and conical sleeve A. If the Davy-screen 13 and the aforesaid stabilizer were not present,'the exhaust-stream would preserve its jet-like shape clear through into tube 17, forming-so to speaka central core of directed gas with much less movement in the peripheral area. Nor, if the screen 13 and stabilizer are in place will the effect be mate'rially different. That is to say, the screen 13 and the deflector H are so designed as 'to present little obstruction to the jet, the function of the screen 13 being to prevent backfire, and the function of the deflector H being to keep the gases within the igniting range of the flame 'and at the same time avoid back pressure. .In other words, if the velocit of the jet increases, the excess volume of a ded gas will be checked at deflector H and tend to spill over, as it were, through the perfo- 'right-hand end of tube G and partl(yr rated walls of the stabilizer into the annular space outside of tube G, some of it being even reversed in direction. It is thereby maintained in the flame area and within range of the igniting capacity of the sparkplug. Also flame jets from the burning mass inside of tube G are projected through the holes in walls of that tube into the gas that has overflowed into the annular space around that tube. From said annular space the gas now finds a free outlet without crowding the openings in deflector H. This outlet is partly through the annular space around the through the perforated walls of said tube into the space outside of the aforesaid core or jet. The contraction of the annular space tends to direct part of the flow into the tube to add a suction draft to the part which traverses deflector H. In brief, the excess gas resulting from the increased velocity is not crowded through deflector H but finds added conductive capacity outside of said deflector and yet is kept within the igniting range of the flame burning within tube G. By this means the outflow through tube F as the velocity and quantity rise is not confined within the central jet-core but is more nearly uniform over the entire cross sectional area of that tube. The flame is not interrupted and no material back-pressure has been created.

Coming to the feature of changing composition of the gas and its effect on combusnon-maintenance, I have discovered that the percentage of burnable matter in the exhaust,

which I will here refer to as fuel, can not be reduced below a certain minimum-say about 16 per cent.without interrupting the combustion. But if kept at this minimum or slightly above it, practically the entire fuel where it opens into the pipe. A suitable valve 3 controls the flow in this pipe M. I provide pressure on liquid in the tank by any suitable means, such as a pressure-pump 7 driven by the engine and introducing air by pipe 1 just back of the aforesaid tube B,

pipes 6 and 8. Thus a. small inflow of li uid excess is unobjectionable and can even be made to contribute to the heating effect. So

By combining the aforesaid stabilizing means and the supplementary fuel supply,

I. am able to burn the exhaust without interruption under all practical conditions It may also be remarked that the variations which afifect exhaust combustion are wide and violent, as clearly set forth in the paragraphs of this specification immediately following the brief description of the drawings.

'For purposes of illustration, I have diagrammatically illustrated a pump 18 which may be of any suitable character, for feeding the supplementary fuel. In Fig. 3 the pressure is supplied from the exhaust manifold 0' of the engine. may be employed for this purpose. I have also shown the damper ,11 as controlled by the usual accelerator pedal of the engine. Thereby a call on the engine for greater duty, and consequent greater exhaust velocity, will automatically provide a greater supply of supplementary air.

What I claim as new and desire to secure by Letters Patent is:

1. A device for reburning exhaust gases comprising, a conduit having a mixing chamber, means for introducing exhaust gases and air in said mixing chamber in jet form and at low pressure, said conduit having parallel routes extending therethrough 'for passage of said mixture, one of said routes being positioned so as to be in line with the entering jet, meanswithin the last mentioned route for diverting a portion of the mixture carried by said jet outwardly into'the other route so as to relieve back pressure, and ignitionmeans located between the mixing chamber a and said parallel routes.

2. A device for reburning exhaust gases comprising, a burner for gases which are 1ntroduced at low pressure and at fluctuating velocities comprising a conduit for receiving a stream of such gases,-an injector positioned to introduce air into said conduit, a mixing chamber for receviing said air and said gases so as to produce a combustible mixture, a stabilizer in-said conduit having a passage for said mixture, said stabilizer having a deflector positioned to outwardly difiert an increasing volume of said mixture into a route parallel with but surrounding said passage,

so as to relieve back pressure created by said increasing volume of mixture, and ignition means located between said mixing chamber bustible condition.

and said stabilizer.

3. A device for reburning exhaust gases comprising a burner for exhaust gases which are introduced in jet format low velocity comprising a conduit havinga mixing chamber for receiving said gases, means for intro- Any other suitable meansducing air into said mixing chamber so as to the tube, adeflector member disposed transversely within said second passageway so as to divert a portion of the mixture varying in amount with changes in the jet velocity to relieve back pressure in said conduit, and ignition means located between said mixing chamber and said tube.

4. A device for reburning exhaust gases comprising a burner for exhaust gases having low pressure and fluctuating velocity comprising a conduit provided with a mixing chamber, means for introducing said gases into said mixing chamber in jet form, means for mixing air with said gases in said mixing chamber, a stabilizer consisting of a tube of perforated metal mounted in said conduit so I portion of the gases carried by the jet into the space surrounding said tube so as to relieve back pressure Within the conduit, and ignition means located between the mixing chamber and said tube. a

5. A device for reburning exhaust gases comprising a burner for exhaust gases having fluctuating velocity and low pressure comprising a conduit provided with a mixing chamber, means for introducing gases into said chamber in jet form, means for mixing air with said gases within said mixing chamber, means for diverting a portion of said gases outwardly so as to relieve back pressure, an ignition device between said mixing chamber and said diverting means, and a flame screen extending transversely across said conduit and located between said mixing chamber and said ignition device.-

6. A device for reburning exhaust gases comprising a burner for exhaust gases having variable composition and low pressure comprisinga conduit having a mixing chamher into which the gas is delivered, means for introducing air into said mixing chamber,

stabilizing means within said conduit for conduit for delivering exhaust gases said mixing chamber, an independent fuel supply having means for introducing'additional fuel into said conduit so as to mix with said gases as they enter said mixing chamber and to'maintain said gases in combustible condition, a stabilizer in said burner having means for relieving back pressure created by any increasing volume of combustible mixture, and an ignition device located between sai stabilizer and said mixing chamber.

8. A device for reburningexhaust gases comprising a burner for exhaust engine gases having fluctuating velocity and low pressure comprising a conduit having a mixing chamber, means for introducing said gases into sald'mixing chamber in jet form, means providing a supplementary air inlet control for said mixing chamber, means within saidconduit for stabilizing the combustible mixture so as to relieve back pressure due to any increasing volume of said mixture, ignition means located between the mixing chamber and the stabilizer, and a flame screen positioned transversely of the conduit and located between said mixing chamber and said means for introducing exhaust gases.

9. A device for reburning exhaust gases comprising a burner for exhaust gases comprising a conduit having a mixing chamber, means forintroducing exhaust gases and air into said mixing chamber, a stabilizer located in said burner so as to relieve back pressure created by any increasing volume of the a mixture, an ignitiomdevice between said stabilizer and said mixing chamber, and means at the outlet end of said burner for creating a suction draft therethrough.

Signed at Albany, of New York, this 3rd day of May 1927.

- LOUIS C HYATT.

county of Albany, State 

